net/ipv4: net: prefer strscpy over strcpy

The deprecated helper strcpy() performs no bounds checking on the
destination buffer. This could result in linear overflows beyond
the end of the buffer, leading to all kinds of misbehaviors.
The safe replacement is strscpy() [1].

Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strcpy [1]
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Link: https://patch.msgid.link/20240828123224.3697672-7-lihongbo22@huawei.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/ipv4/ip_tunnel.c

@@ -1326,7 +1326,7 @@ int ip_tunnel_init(struct net_device *dev)
 
 	tunnel->dev = dev;
 	tunnel->net = dev_net(dev);
-	strcpy(tunnel->parms.name, dev->name);
+	strscpy(tunnel->parms.name, dev->name);
 	iph->version		= 4;
 	iph->ihl		= 5;
 

net/ipv4/netfilter/arp_tables.c

@@ -826,7 +826,7 @@ static int get_info(struct net *net, void __user *user, const int *len)
 		       sizeof(info.underflow));
 		info.num_entries = private->number;
 		info.size = private->size;
-		strcpy(info.name, name);
+		strscpy(info.name, name);
 
 		if (copy_to_user(user, &info, *len) != 0)
 			ret = -EFAULT;

net/ipv4/netfilter/ip_tables.c

@@ -981,7 +981,7 @@ static int get_info(struct net *net, void __user *user, const int *len)
 		       sizeof(info.underflow));
 		info.num_entries = private->number;
 		info.size = private->size;
-		strcpy(info.name, name);
+		strscpy(info.name, name);
 
 		if (copy_to_user(user, &info, *len) != 0)
 			ret = -EFAULT;